Carburetor construction



N 1967 I J. F. DENINE 3,352,545

I CARBURETOR CONSTRUCTION Filed May 31, 1966 /2 i 2 Z Z7 7 g C/akn 0mm A7'7'02/VEK United States Patent. Office 3,352,545 Patented Nov. 14, 19673,352,545 CARBURETGR CONSTRUCTION John F. Denine, 180 Lincoln St.,Hudson, Mass. 01749 Filed May 31, 1966, Ser. No. 554,045 12 Claims. (Cl.261-41) ABSTRACT OF THE DISCLOSURE A carburetor apparatus for improvingthe efilciency and performance of internal combustion engines. Thecarburetor comprises a fuel regulating idle screw formed of a relativelyporous material which both disperses and aerates fuel delivered to theengine.

This invention relates generally to carburetors for use with internalcombustion engines and more particularly to a novel fuel supply systemfor such carburetors.

A large variety of carburetor developments have resulted from attemptsto improve the efiiciency and performance of internal combustionengines. These developments have included, for example, multi-stage fuelsysterns, automatic chokes, fuel flow metering devices, economizing andenriching devices, etc. The "common object for many of the priorimprovements was to obtain a more thoroughly mixed fuel and air chargewhich would result in a more complete combustion of the fuel uponignition. Such a result would reduce or eliminate many of the inherentproblems associated with internal combustion engines such as carbondeposition, relatively low efiiciency, poor cold weather operation,rough engine operation at low speeds and during acceleration, etc.However, the prior carburetor improvements have failed to fully satisfythe desired objective or to fully eliminate the problems.

The object of this invention, therefore, is to provide for use withinternal combustion engines an improved carburetor which improves boththe efiiciency and performance characteristics of internal combustionengines.

One feature of this invention is the provision for internal combustionengines of an improved carburetor having a primary-fuel supply systemwhich discharges fuel from a fuel reservoir into a mixing conduitanterior to a throttle valve and an idle fuel system which dischargesfuel from the fuel reservoir through an idle port into the mixingconduit posterior of the throttle valve and wherein the idle fuel systemincludes an adjustment element composed of a relatively porous materialand adapted to regulate the rate of fuel flow through the idle port. Therelatively porous adjustment element disperses and aerates the fuelwhich in turn improves engine efiiciency and performance.

Another feature of this invention is the provision for internalcombustion engines of an improved carburetor having a primary fuelsystem adapted to discharge fuel from a fuel reservoir into a mixingconduit anterior to a throttling valve and including a fixed fuel nozzlecomposed of a relatively porous material and projecting into the mixingconduit adjacent a venturi. As above, the porous nozzle effects agreatly improved dispersion and aeration of the injected fuel to therebyimprove engine efliciency and performance.

Another feature of this invention is the provision for internalcombustion engines of a carburetor of the above featured type wherein anadjustable idle screw forms at least a part of the adjustment element.

Another feature of this invention is the provision of an internalcombustion carburetor of the above featured types wherein the relativelyporous material used for the fuel nozzle and idle adjustment is sinteredmetal.

Another feature of this invention is the provision for internalcombustion engines of a carburetor of the above featured types whereinthe relatively porous material utilized for the fuel nozzle andadjustment element possesses an open porosity of between 30 and percent.

Another feature of this invention is the provision for internalcombustion engines of a carburetor of the above featured types whereinthe relatively porous material used for the fuel nozzle and theadjustment element has an average pore size of between 2 and 50 microns.

These and other objects and features of the present invention willbecome more apparent upon a perusal of the following specification takenin conjunction with the accompanying drawing which is a schematiccross-section showing a preferred embodiment of the invention.

Referring now to the drawing there is shown the mixing conduit 11including the air born 12, the venturi section 13 and the throttle bore14. Positioned within the mixing conduit 11 is the throttle valve 15Which is mounted for rotation with the throttle shaft 16. The fuel bowl17 functions as a fuel reservoir for the device.

The primary fuel supply system 21 including the fuel well 22, the highspeed fuel passage 23 and the fuel nozzle 24 provides a fuel dischargepath between the fuel bowl 17 and the mixing conduit 11. The fuel nozzle24 projects into the mixing conduit 11 adjacent the venturi portion 13.Regulating the flow rate of fuel from the fuel bowl 17 is the meteringorifice member 25 and fuel metering rod 26. The metering rod 26 isactuated by a conventional mechanism (not shown) so as to provide acontrolled fuel flow rate.

The idle fuel supply system 31 includes the idle fuel passage 32 whichprovides a fuel flow path between the idle ports 33 and 34 and the idletube 35 which opens into the high speed fuel passage 23. The upper idleport 33 opens into the mixing conduit 11 anterior to the throttle valve15 when in a closed position and the lower idle port 34 opens into themixing conduit posterior to the throttle valve 17 when in the closedposition. Supported by threads in the wall of the mixing conduit 11 isthe idle screw 36 with valve stem 37 which extends an ad justabledistance into the lower idle port 34 so as to regulate fuel flowtherethrough.

According to the invention the fuel nozzle 24 and the idle screw 36 arecomposed of a relatively porous material. During movement along thesurfaces of the porous material and through the pores therein, fuel isbroken up into an extremely fine dispersion and thoroughly aeratedbefore injection into the mixing conduit 11. Also, because of theincreased area of exposed fuel surface a substantial increase in therate of fuel evaporation occurs. The fuel evaporation which occurs onthe surfaces of the porous material and within the mixing conduit 11provides a beneficial cooling of the entire carburetor body. As a resultof the improved fuel dispersion and carburetor cooling a much morecomplete fuel combustion is obtained. Accordingly, there is obtained areduction in fuel consumption, smoother engine performance, increasedpower, reduction of carbon depositions, improved cold weather engineperformance, etc.

While sintered metals such as steel, nickel, and particularly bronze arepreferable for use as the relatively porous material in the fuel nozzle24 and idle screw 36, other porous materials are suitable. These caninclude, for example, composite materials formed by porous granules ofalumina, silicon carbide, mulite, etc., bonded together with a suitableceramic. It is important, however, that the material possess arelatively high open porosity so as to be permeable to both air andfuel. For example, it has been found extremely desirable for reasons ofpermeability and strength that the material possess an open .3 porosityof between 30 and 60 percent as established by the following formula:

where P represents the percentage of open porosity, W represents theweight of a material sample in air, W represents the weight of the samematerial sample after immersion in a given liquid, D represents theapparent density of the sample material and D represents the density ofthe given liquid. It has also been found desirable that the materialhave pores with an average size of between 2 and 50 microns.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. For example, the fuelnozzle 24 or the idle screw 36 can be composite units composed of bothporous and solid materials. In that case, the portion of the elementwhich is most effective in dispersing the fuel would preferably becomposed of a porous substance. Thus, the valve stem 37 could be porousand the threaded base of the idle screw 36 could be solid. Similarly,the end of the nozzle 24 which projects into the mixing conduit 11 couldbe porous and the nozzle base supported within the fuel passage 23 couldbe solid. It is, therefore, to be understood that within the scope ofthe appended claims the invention may be practiced otherwise than asspecifically described.

What is claimed is:

1. A carburetor for use in an internal combustion engine and comprisinga mixing conduit, a fuel reservoir, a rotatable throtle shaft extendinginto said mixing conduit, a throttle valve mounted on for rotation withsaid throttle shaft, venturi means in said mixing conduit anterior tosaid throttle valve, a primary (fuel supply system adapted to dischargefuel from said fuel reservoir to said mixing conduit adjacent saidventuri means in response to engine demands, a metering means adapted toregulate the amount of fuel passing from said fuel reservoir to saidmain supply system, an idle fuel system adapted to discharge fuel fromsaid fuel reservoir through an idle port which opens into said mixingconduit posterior tosaid throttle valve when in a substantially closedposition, and said idle fuel system including an adjustment meansextending into said idle port so as to regulate the .rate of fuel flowtherethrough, and wherein said adjustment means is composed of arelatively porous material.

2. A carburetor according to claim 1 wherein said relatively porousmaterial is sintered metal. 7

3. A carburetor according to claim 1 wherein said relatively porousmaterial has an open porosity of between thirty and sixty percent.

4. A carburetor according to claim 3 wherein said relatively porousmaterial is sintered metal.

5. A carburetor according to claim 1 wherein the pores in saidrelatively porous material have an average size of between two and fiftymicrons.

6. A carburetor according to claim 1 including an adjustable idle screwwhich comprises said adjustment means.

7. A carburetor according to claim 6 wherein said relatively porousmaterial is sintered metal.

8. A carburetor according to claim 7 wherein said relatively porousmaterial has an open porosity of between thirty and sixty percent.

9. A carburetor according to claim 1 wherein said primary fuel supplysystem includes a fixed fuel nozzle at least partly composed of arelatively porous material and projecting into said mixing conduitadjacent said venturi means.

10. A carburetor according to claim 9 wherein both said relativelyporous materials comprise sintered metal,

11. A carburetor according to claim 9 wherein both said relativelyporous materials have an open porosity of between thirty and sixtypercent.

12. A carburetor according to claim 11 wherein both said relativelyporous materials comprise sintered metal.

References Cited UNITED STATES PATENTS Re. 24,232 10/ 1956 Johnson261-99 X 1,857,565 5/1932 Pahl et al. 261-99 2,530,716 11/ 1950 Meynier261-99 X 2,551,114 5/1951 Goddard 261-99 X 2,711,885 6/ 1955 Moseley.

2,816,573 12/1957 Kaddis et al. 3,166,611 l/1965 Conant et al. 3,199,8478/1965 Wahnish 261-99 X FOREIGN PATENTS 819,574 9/1959 Great Britain.

HARRY B. THORNTON, Primary Examiner. TIM R. MILES, Assistant Examiner, V

1. A CARBURETOR FOR USE IN AN INTERNAL COMBUSTION ENGINE AND COMPRISINGA MIXING CONDUIT, A FUEL RESERVOIR, A ROTATABLE THROTLE SHAFT EXTENDINGINTO SAID MIXING CONDUIT, A THROTTLE VALVE MOUNTED ON FOR ROTATION WITHSAID THROTTLE SHAFT, VENTURI MEANS IN SAID MIXING CONDUIT ANTERIOR TOSAID THROTTLE VALVE, A PRIMARY FUEL SUPPLY SYSTEM ADAPTED TO DISCHARGEFUEL FROM SAID FUEL RESERVOIR TO SAID MIXING CONDUIT ADJACENT SAIDVENTURI MEANS IN RESPONSE TO ENGINE DEMANDS, A METERING MEANS ADAPTED TOREGULATE THE AMOUNT OF FUEL PASSING FROM SAID FUEL RESERVOIR TO SAIDMAIN SUPPLY SYSTEM, AN IDLE FUEL SYSTEM ADAPTED TO DISCHARGE FUEL FROMSAID FUEL RESERVOIR THROUGH AN IDLE PORT WHICH OPENS INTO SAID MIXINGCONDUIT POSTERIOR TO SAID THROTTLE VALVE WHEN IN A SUBSTANTIALLY CLOSEDPOSITION, AND SAID IDLE FUEL SYSTEM INCLUDING AN ADJUSTMENT MEANSEXTENDING INTO SAID IDLE PORT SO AS TO REGULATE THE RATE OF FUEL FLOWTHERETHROUGH, AND WHEREIN SAID ADJUSTMENT MEANS IS COMPOSED OF ARELATIVELY POROUS MATERIAL.